Mechanical linkage



' P 1953 v o. s. CHISHOLM 3,379,069

MECHANICAL LINKAGE Filed March 21, 1966 1 NVEN TOR. D0 ug/oa 6. 6618/70/07 HGENT United States Patent 3,379,069 MECHANICAL LINKAGE Douglas S. Chisholm, Midland, Mich., assignor to The Dow Chemical Company, Midland, Mich., a corporation of Delaware Filed Mar. 21, 1966, Ser. No. 535,830 5 Claims. (Cl. 74-11) This invention relates to an improved mechanical linkage. It more particularly relates to an improved mechanical linkage capable of positioning a point on a predetermined curved line or surface.

Frequently in the construction of buildings having curved surfaces it is desirable to provide a guide or a tool which is readily positionable on or adjacent to the building structure in such a manner that the required design is adhered to. In cases of circular or spherical structures this is readily accomplished, for example, by pivoting an arm on the center of the desired structure. However, oftentimes it is desirable to generate structures wherein there is no ready access to the center. For example, in a spherical or spheroidal dome often a suitable geometric center is not available or in the case of a dome having an elliptical cross sectional configuration the centers of generation may be remote and inaccessible, such as being positioned below ground level. oftentimes it is desired to support a construction unit such as a bricklaying machine or the like at the end of a boom or arm and position the terminal portion of the boom in such a manner that it serves as a guide and determines the final form of the structure. Such a technique is particularly advantageous when buildings are constructed from strips or portions of synthetic resinous foam which are adhered together to form the desired configuration.

It is an object of this invention to provide an improved mechanical linkage adapted to position an arm on a desired curved surface.

A further object of this invention is to provide a mechanical linkage which will generate a spherical or non-spherical surface of rotation.

A further object of this invention is to provide an apparatus for the positioning of an operating mechanism in a guided pattern capable of generating a dome-like surface.

These benefits and other advantages in accordance with the present invention are achieved in an apparatus adapted to multiply linear motion, the apparatus comprising a frame, the frame having a first end and a second end, a first Wheel pair rotatably mounted generally adjacent the first end and a second wheel pair rotatably mounted generally adjacent the second end, each of the first and second wheel pairs comprising at least first and second wheels. The first wheels of the first and second wheel pairs are of like pitch diameter and also the second wheels have like pitch diameters. A mount is slidably disposed on the frame and adapted for sliding movement between the first and second wheel pairs. The mount has pivotally afiixed thereto first and second idler wheels. An endless linear motion transmitting means extends between the first wheel of the second wheel pair, from the first wheel of the first wheel pair to an idler wheel, about the idler wheel to the second wheel of the first wheel pair, from the second wheel of the first wheel pair to the second Wheel of the second wheel pair, about the remaining idler wheel to the first wheel of the second Wheel pair and each of the wheels being capable of independent rotary motion.

Further features and advantages of the present invention will become more apparent from the following specification taken in connection with the drawing wherein:

3,3 Patented Apr. 23, 1968 ice FIGURE 1 is a schematic representation of an apparatus in accordance with present invention; and

FIGURE 2 depicts an alternate embodiment of an apparatus in accordance with the present invention particularly suited for positioning and operating the mechanism on a curved surface.

In FIGURE 1 there is depicted an apparatus in accordanace with the invention generally designated by the reference numeral 10. The apparatus 10 comprises in cooperative combination a frame or support arm 11. The support arm 11 has a first end 12 and a second end 13'. A first wheel pair generally designated by the reference numeral 15 is pivotally disposed adjacent the first end 12. The wheel pair 15 comprises a first Wheel 16 and a second wheel 17. By the term wheel is meant a pulley gear, sprocket gear, drum or the like. The wheels 16- and 17 are generally coaxially disposed, and are free to rotate about a pivot or stub shaft 19. A second wheel pair 21 is disposed adjacent the second end 13 of the frame 11. The second wheel pair 12 comprises a first wheel 22 and a second wheel 23. The wheels 22 and 23 are substantially coaxial'ly disposed and rotate independently about a pivot or stub shaft 24. The frame 11 defines an opening or guide means 26 extending generally between the first Wheel pair 15 and the second wheel pair 21. A wheel mount 27 is slidably disposed within the guide means 26. The wheel mount 27 has pivotally disposed thereon a first idler wheel 28 and a second idler wheel 29. Beneficially the first wheel pair 15, the second wheel pair 21 and the idler wheels 28 and 29 are disposed in generally coplanar relationship. A linear motion transmitting means 31 passes about the first wheel 16 of the first wheel pair 15, about the first idler wheel 28, about the second Wheel 17 of the first wheel pair 15 to the second wheel 23 of the second wheel pair 21 and about the second idler wheel 29 to the first wheel 22 of the second wheel pair 21 thence to the first wheel 16 of the first wheel pair 15 to form a continuous loop. A point P is disposed on the wheel carrier 27 and and a point P on the linear transmission means extending directly between the first wheel 16 of the first wheel pair 15 and the first wheel 22 of the second wheel pair 21.

In operation of the apparatus 10 of FIGURE 1, one has in effect a motion multiplying or dividing apparatus. As the point P is moved to or from the first wheel pair 15 a similar motion of the point P on the wheel carrier occurs permitting positive and rigid positioning in either direction. The ratio of the motion between the point P on the wheel carrier 27 and P on the linear transmission means is obtained employing the equation wherein D represents the diameter of the first wheel in either of the wheel pairs and D is the diameter of each of the second wheels in both of the wheel pairs. The wheel pairs 15 and 21 may 'be sprocket gears of equal pitch diameter or drums of equal diameter and equal circumference. The diameters of the idler wheels 28 and 29 are not critical, beneficially they are equal and are selected in accordance with good engineering principles for the particular motion transmitting means selected such as a chain, cable, belt or the 'like. By selecting the desired ratios between the first and second wheels of the wheel pairs, almost any desired ratio of travel may be obtained between P and P In FIGURE 2 there is illustrated an apparatus in accordance with the invention generally designated by the reference numeral 40. The apparatus 40 comprises a cooperative combination, a base generally designated by the reference numeral 41. The base 41 is pivotally affixed to the earth or other suitable support such as the support 42 by means of a pivot 43. The pivot 43 is gene-rally centrally disposed on the base. A peripheral support or wheel 44 is beneficially provided and affixed to the base 41 and adapted to engage the support 42 and permit free rotation of the base 41. A template or model curve 45 is affixed to the base 41 remote from the surface 42. The template 45 defines a model curve and edge 46 which is a model of a desired curve which is to be reproduced on a different scale. A pivot 48 is rigidly atfixed to the base 41. Generally adjacent the pivot 43 and remote from the support 42, an arm 49 is affixed to the pivot 48 by means of a first end 50. The arm 49 has a second end 51 remotely dispose from the pivot 48. An arm positioning means 52 is disposed adjacent the pivot 48 and adapted to pivot the arm 49 in a plane generally parallel to a plane containing the axis of the pivot 43. A first wheel pair 54 is disposed adjacent to the first end of the arm 49. The first wheel pair 54 comprises a first wheel 55 and a second wheel 56. A second wheel pair 58 is pivotally mounted adjacent the second end 51 of the arm 49. The second wheels pair 58 comprises a first wheel 59 and a second wheel 60'. An idler wheel support 62 is slidably aflixed to the arm 49 and positioned generally adjacent the template 45. A follower 63 is affixed to the idler wheel support 62 and adapted to engage the edge 46 and is maintained in contact therewith. The idler wheel support carries the first idler wheel 65 and the second idler wheel 66. An operating means 63 is slidably secured to the arm 49 generally adjacent the second end 51. A motion transmitting means such as a cable, belt or chain is secured to the operating means 68 at location 71. The motion transmitting means 70 passes from the location 71 to the first wheel 55, about the first wheel 55, around the idler wheel 65, about the second wheel 56, to the second wheel 60, to the second idler wheel 66, about the first wheel 59 of the second wheel pair and to the location 71 substantially in the same manner as the motion transmitting means 31 of FIG- URE l.

The apparatus 40 seen in FIGURE 2 is eminently adapted to reproduce or trace curved surfaces which correspond to the model surface or guide curve of the edge 46 of the template 45. As the arm 49 is pivoted above the pivot point 48 by means of the arm elevating or rotating mechanism 52 the gear support 62 having the follower 63 is maintained in contact with the edge 46 and the operating means 68, which beneficially may be a construction apparatus or foam depositing head, moves a distance which is directly proportional to the displacement of the gear support 62 on the arm 49. Thus, accurately tracing an enlarged version of the curve 46 by simultaneous rotation of the base 41 the operating means 68 generates a surface of rotation.

As is apparent from the foregoing specification, the apparatus of the present in invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. For this reason, it is to be fully understood that all of the foregoing is intended to be merely illustrative and is not to be construed or interpreted as being restrictive or otherwise limiting of the present invention, excepting as it is set forth and defined in the hereto appended claims.

What is claimed is:

1. An apparatus particularly suited and adapted to multiply linear motion; the apparatus comprising a frame; the frame having a first and second end, a first wheel pair rotatably mounted generally adjacent the first end, a second wheel pair rotatably mounted adjacent the second end, the first and second wheel pairs comprising at least first and second wheels, the first wheels of the first and second wheel pairs being of like pitch diameter, and the second wheels having like pitch diameter; a mount slidably disposed upon the frame and adapted to slidably move between the first and second wheel pairs, the mount having affixed thereto first and second idler wheels, an endless linear motion transmitting means extending between the first wheel of the second wheel pair, from the first wheel of the first wheel pair to one of the idler wheels, about the idler Wheel to the second wheel of the first wheel pair, from the second wheel of the first wheel pair to the second wheel of the second wheel air, about the remaining idler wheel to the first Wheel of the second Wheel pair and each of the wheels being capable of independent rotary motion.

2. The apparatus of claim 1 wherein the wheels are sprocket wheels and the linear motion transmitting means is a chain adapted to peripherally engage the sprocket wheels.

3. The apparatus of claim 1 wherein the first end of the frame is pivotally affixed by means of a pivot to a base, the base having a base pivot having an axis of rotation generally normal to the axis of rotation of the pivot engaging first end of the frame.

4. The apparatus of claim 3 wherein the slidable wheel mount has a follower affixed thereto, a template disposed adjacent to the frame and adapted to be engaged by the follower as the frame is swung about the pivot of the second end.

5. The apparatus of claim 4 wherein an operating means is affixed to a point on the linear motion transmitting means extending between the first wheel of the first wheel pair and the second wheel of the second wheel pair.

No references cited.

FRED C. MATTERN, JR., Primary Examiner.

C. J. HUSAR, Assistant Examiner. 

1. AN APPARATUS PARTICULARLY SUITED AND ADAPTED TO MULTIPLY LINEAR MOTION; THE APPARATUS COMPRSING A FRAME; THE FRAME HAVING A FIRST AND SECOND END, A FIRST WHEEL PAIR ROTATABLY MOUNTED GENERALLY ADJACENT THE FIRST END, A SECOND WHEEL PAIR ROTATABLY MOUNTED ADJACENT THE SECOND END, THE FIRST AND SECOND WHEEL PAIRS COMPRISING AT LEAST FIRST AND SECOND WHEELS, THE FIRST WHEELS OF THE FIRST AND SECOND WHEEL PAIRS BEING OF LIKE PITCH DIAMETER, AND THE SECOND WHEELS HAVING LIKE PITCH DIAMETER; A MOUNT SLIDABLY DISPOSED UPON THE FRAME AND ADAPTED TO SLIDABLY MOVE BETWEEN THE FIRST AND SECOND WHEEL PAIRS, THE MOUNT HAVING AFFIXED THERETO FIRST AND SECOND IDLER WHEELS, AN ENDLESS LINEAR MOTION TRANSMITTING MEANS EXTENDING BETWEEN THE FIRST WHEEL OF THE SECOND WHEEL PAIR, FROM THE FIRST WHEEL OF THE FIRST WHEEL PAIR TO ONE OF THE IDLER WHEELS, ABOUT THE IDLER WHEEL TO THE SECOND WHEEL OF THE FIRST WHEEL PAIR, FROM THE SECOND WHEEL OF THE FIRST WHEEL PAIR TO THE SECOND WHEEL OF THE SECOND WHEEL AIR, ABOUT THE REMAINING IDLER WHEEL TO THE FIRST WHEEL OF THE SECOND WHEEL PAIR AND EACH OF THE WHEELS BEING CAPABLE OF INDEPENDENT ROTARY MOTION. 